# Apache Tomcat: LockOutRealm treats user names as case-sensitive

Advisory record · `GHSA-5mp6-jrq3-r938`

- **Identifiers:** `GHSA-5mp6-jrq3-r938` · `BIT-tomcat-2026-43513` · `CVE-2026-43513`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-178](https://cwe.mitre.org/data/definitions/178.html)
- **Tags:** [CWE-178](https://agentprime.io/advisories/tag/cwe-178.md)
- **Published:** 12 May 2026
- **Updated:** 11 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 12 May 2026, 18:30 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `org.apache.tomcat.embed:tomcat-embed-core` (Maven): affected `<9.0.118 || >=10.1.0-M1, <10.1.55 || >=11.0.0-M1, <11.0.22`; fixed in `9.0.118`, `10.1.55`, `11.0.22`
- `org.apache.tomcat:tomcat` (Maven): affected `<9.0.118 || >=10.1.0-M1, <10.1.55 || >=11.0.0-M1, <11.0.22`; fixed in `9.0.118`, `10.1.55`, `11.0.22`
- `org.apache.tomcat:tomcat-catalina` (Maven): affected `<9.0.118 || >=10.1.0-M1, <10.1.55 || >=11.0.0-M1, <11.0.22`; fixed in `9.0.118`, `10.1.55`, `11.0.22`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 7.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.0050, the 43rd percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:16 UTC: First seen by agentprime
- 31 Oct 2026, 14:16 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-5mp6-jrq3-r938)

## Sources

- [GitHub Advisory Database: GHSA-5mp6-jrq3-r938](https://github.com/advisories/GHSA-5mp6-jrq3-r938)
- [OSV: GHSA-5mp6-jrq3-r938](https://osv.dev/vulnerability/GHSA-5mp6-jrq3-r938)
- <https://nvd.nist.gov/vuln/detail/CVE-2026-43513>
- <https://github.com/apache/tomcat/commit/4a90d3fa93988c447cd5bb7482f76ff70d7f15c2>
- <https://github.com/apache/tomcat/commit/6dd75beb55bd42fc5f78e929596b25018cd17717>
- <https://github.com/apache/tomcat/commit/83f3e51df7b87f5f6e626951c575ded1a512e8ef>
- <https://github.com/apache/tomcat>
- <https://lists.apache.org/thread/ytjcgldshj73lcnd1sh95od5hrghwogp>
- <https://tomcat.apache.org/security-10.html>
- <https://tomcat.apache.org/security-11.html>
- <https://tomcat.apache.org/security-9.html>
- <http://www.openwall.com/lists/oss-security/2026/05/12/9>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-5mp6-jrq3-r938>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-5mp6-jrq3-r938/>. Everything for agents: <https://agentprime.io/llms.txt>.